Explosive composition containing polybutene



Patented Feb. 13, 1951 EXPLOSIV E COMPOSITION CONTAINING POLYBUTEN E a William J. Taylor, Tamaqua, Pa., assignor to Atlas Powder Company,- Wilmington, Del., a corporation of Delaware No Drawing. Application October 28', 1949, Serial No. 124,239

14 Claims. (Cl. 52-5)' The present application relates to a novel explosive and more particularly it relates to a dynamite possessing desirable characteristics.

An object 015 the present invention is the provision of a dynamitewhicn is readily packed into cartridges and is not subject to sifting out of cartridges containing it.

Another 'object'of the-*invention is the provision of a dynamite which holds its shape and is not free running.

A. further object of the. inventionis a provisionof'a dynamite which is cohesive.

Other'objects of the invention will be apparent fromthe following description.

Some "dynamites contain relatively high proportions of liquid ingredients'mixed with granular ingredients. Nitroglycerine, for example, is a: common liquid ingredient in dynamites. Dynamites containing a high proportion of liquid ingredients are more or less plastic and cohesive.

Particularly is this true of dynamites containingtnitrfoglycerine gelatinized with nitro cellulose. This'cohesiveness and plasticity is a valuable characteristic-of such. dynamites. them easy to pack into cartridges and it prevents their sifting fromcartr'idges in which they are packed Inaddition, cartridges containing such d'ynamites can be out without incurring loss and hazard dueto spillage of explosive.

However, for many uses, it is not desirable that dynamites containhigh proportions of liquid ingredients. Many nitroglycerine dynamites, for example, are prepared with amounts of nitroglycerine below 20%. Such dynamites and others containing low proportions of liquids contain a high proportion of dry powdered or granular ingredients Relatively dry dynamites suffer from lack of cohesiveness, They are difiicult to pack in cartridges; they tend to'sift out of cartridges in which they are packed, and cartridges containing them cannot readily be cut without spilling the dynamite. Furthermore, such dynamites are difiicult to load into upwardly pitching bore holes when the shells have been slit to make-the cartridges easily compacted.

By means of the present invention, powdery granular dynamites, such as those just described, may be prepared in cohesive form so that they 7 have thedesirable properties of the more plastic types of dynamites.

According to the present invention, there is included, with the usual ingredients of a dyna- It makes mite which normally non'cohesive, a viscous liquid polybutene product selected from the group consisting of a viscous liquid polybutene preferably a liquid polybutene possessing tackines's, and a tacky solution of a solid rubbery polymer in a liquid polybutene. Polybutene is also'known as polymerized butene, polymerized isobutylene, or polyisobutylene. The solid rubbery polymer dissolved inthe liquid polybu-tene maybe any of a variety of solid, plastic, or rubber-like materials, and solid rubbery polybutene, natural rubber, or a synthetic rubber soluble in the polyb'utene'may'be given as examples. Since the polymers dissolved in the polybuteneare solid and rubbery or plastic, they areof relatively high molecular weight.

Theviscousliquid product, although present in a small amount, is effective in converting the relatively free-flowing explosive composition into a cohesive produ'ctand tests have shown the sticky liquid product,'when present in the explosive composition as described herein, does not deleteriously affect the explosive properties of compositions containing it. Thus, the sensitiveness and'velo'city of the composition is not appreciably affected-by the presence of the product in the composition.

The viscosity and stickiness or tackiness of polybutenedepends on the degree of polymerization thereof as indicated by the molecular weight 7 of the product; and polybutene, as do most polymeric materials, progresses from a liquid of relatively low viscosity and tackiness through a liquid'product of relatively high viscosity and characterized by a greater degree of tackiness to a plastic or rubber-like solid, as the degree of polymerization of the product increases.

'When reference is made herein to molecular i ntrinsic viscosity Molecular we1ght 00000318 The liquid polybutenes are conveniently identified according to their viscosities determined with the 'Saybolt Universal viscosimeter and the viscosities hereinafter set forth are expressed as SSU (seconds Saybolt Universal), the temperature of the liquid used in the determination of viscosity being 210 F. for the more viscous liquids and. 100 F. for the less viscous liquids. Liquids whose viscosity at 210 F. is below 50 SSU are measured at 100 F., and in the case of the liquid polybutenes, a viscosity of 50 SSU (210 F.) corresponds to approximately 350 SSU (100 F.)

When the liquid product employed in the dynamite composition is a polybutene per se, the viscosity thereof may vary over a wide range but advantageously it will have a viscosity of at least approximately 180 SSU (100 F.) and preferably the polybutene will have been polymerized to the stage where the product itself is a liquid of relatively high viscosity and possesses tackiness. It has been found that a polybutene having a viscosity from about 180 SSU (100 F.)

to about 2700 SSU (210 F.) and preferably from about 135 SSU (210 F.) to about 620 SSU (210 F.), will possess especially desirable properties so that it will impart high cohesiveness to a relatively free flowing dynamite composition. Thus, when the polybutene has a viscosity of at least approximately 135 SSU (210 F.), it will possess tackiness which aids in imparting the desirable properties to a free flowing dynamite composition. When the viscosity is above about 620 SSU (210 F.), the polybutene will be of relatively high viscosity at normal atmospheric temperatures and it may be desirable to warm it to reduce the viscosity before it is mixed with the dynamite in-' gredients.

In the preferred embodiment of the invention Where the tacky liquid product comprises a solution of a solid, rubbery polymer in a liquid polybutene, the liquid polybutene employed will have been polymerized only to a relatively low degree where it will be a liquid of relatively low viscosity, for example, the polybutene will advantageously have a viscosity between about 50 SSU (100 F.) and about 620 SSU (210 F.), preferably between about 100 SSU (100 F.) and about 300 SSU (210 F.). Specific examples of polybutenes are products having viscosities of 52, 154, and 222 SSU (210 F.). As indicated above, the desired tackiness and viscosity is imparted to the liquid polybutene of relatively low molecular weight by dissolving therein a solid, rubberlike polymer, that is a high molecular weight polymer that is soluble in the liquid polybutene. While, as stated, the solid rubbery polymer may be of a variety of polymeric materials, advantageously the solid, rubber-like polymer is a polybutene or natural rubber. When the solid rubberlike polymer is polybutene, it may be any polybutene product having such properties, and generally the molecular weight of the polybutene will be between about 40,000 and about 120,000,

- although solid polymers of lower or higher moleerally, between about 1% and about 10% of the solid rubbery polymer will be dissolved in the polybutene. The amount dissolved in any particular case will depend upon the molecular weight of the liquid polybutene and of the solid rubbery polymer and upon the viscosity and tackiness of the solution desired. Even though the resulting solution may have a viscosity corre sponding to that of a liquid polybutene per se, the solution will be characterized by a greater tackiness and it is for this reason that the use of the described solution is preferred. In preparing the solution, it may be necessary to heat the mixture of the liquid polybutene and the solid polymer and, as in the case of a liquid polybutene per se, the solution if desired may be warmed to reduce its viscosity before mixing it with the dynamite ingredients.

The following are examples of solutions that have been used in explosive compositions which are relatively free-flowing to impart cohesiveness thereto:

Solution A 2 parts of a solid, rubber-like polybutene having a molecular weight of about 80,000 were dissolved in 60 parts of a liquid polybutene having a viscosity of about 222 SSU (210 F.). The solution was viscous and very tacky.

Solution B A solution was prepared containing 6% of the high molecular weight polybutene used in the preparation of Solution A in a liquid polybutene having a viscosity of about 154 SSU (210 F.). The solution was very tacky but not so viscous as Solution A.

Solution C A solution was prepared containing 6% of the high molecular weight polymer used in the preparation of Solution A dissolved in a liquid polybutene of a viscosity of about 52 SSU (210 F.). The solution was characterized by excellent tackiness but was less viscous than Solution B.

Solution E I A solution was prepared containing '7 /2% of the high molecular weight polymer used in the preparation of Solution A dissolved in a liquid polybutene of a viscosity of about 52 SSU (210 F.) The solution was very tacky and was slightly more viscous than Solution D.

Solution F A solution was prepared containing 4% of a solid rubbery polybutene having a molecular weight of about 100,000 in a liquid polybutene of a viscosity of about 52 SSU (210 F.). The solution was characterized by a fairly high viscosity and by good tackiness.

Solution G A solution was prepared which corresponded to Solution F except that the solid rubbery poly- 'mer had a molecular Weight of about 120,000.

The resulting solution was slightly more viscous and tacky than Solution F.

Solution H 4 parts of natural rubber (smoked sheet) were dissolved in 96 parts of a liquid polybutene having a viscosity of about 222 SSU (210 F.). The resulting solution was tacky and viscous.

Solution J A solution of 3% smoked sheet rubber was dissolved in. afliquid polybutene having 11a viscosity of about. 222:SSU9(210ZF.).. The solutioniwas slightly less viscous than Solution H but possessed good tackiness.

Solution. If

A solution of 2% smoked sheet rubber was dis solved in a liquidpolybutene having aviscosity of.- about 222 SSU (210. 'F.)'. The: solution." was slightly less tacky andviscous than Solution-J;

The. amount of the 'tackyliquid, Whether itiibe the liquid polybutene per se or the solution of the solid, rubber polymer -in..the liquidpolybutene mixed with the dynamitezingredientsinpreparing the cohesive productof the invention, will depend upon the cohesiveness desired in .the ex-. plosive. In genera1,'amounts of the tacky liquid as low as 0.2% based on the weight of the explosive are found to produce desirable improvements in cohesiveness. On the other hand, amounts above about basedon the weight of the explosive do not usually produce much increased beneficial effects, although amounts above .that figure may be used if "desired, provided, 'of course, that the amount employed does not deleteriously affect the desired properties of the explosive. Preferably, the amount of the tacky liquid employed 'Willbe betweenabout 0.5%- andabout 2%.

As has been stated, the invention is applicable for use in connection with anyof the types of dynamite that tend to sift or are loose or free-running to convert the dynamite into a product which will holdiitsshape. As is well; known, dynamites contain, in addition to anaexplosive sensitizer','one or more oxidizingsalts and one or more fuels ,'such. as wood pulp, coal, apricot pit pulp, bagasse, corn;- flour, sulphur, or the like,,which-serve also as abe sorbents or. adsorbents for .the liquid. senitizers; the proportion of oxidizing saltsto fuel being such, that the oxygen balance of the explosive, exclusive of :the wrapper," generallywill' lie between about '35'% and about-+10%, usually between about 4i% and about +10%. For a discussion of the oxygen balances of explosives, see Bureau of Mines Bulletin. 219 (1923), pp. 102405." Examples of sensitizers are nitroglycerine, or nitro aromatics like trinitrotoluene, dinitrotohiene, and mononitrotoluene, with or without'highly com= bustible powders such as aluminum dust. The term nitroglycerine includes the various mixtures commonly called nitroglycerine in the explosive industry, common ingredients ofsuoh m'ixtures, other than nitroglycerine; being: nitr'ogly col, nitro sugars, and nitrates of higher polyhydric-alcohols. Other dynamite ingredients such as, for example, antacid materials, like calcium carbonate, may be, and usually are, also included.

In general, it maybe said that the. practical utility of the invention-is; diminished in formulations having in excess of about %"of liquid:in-- gredients. Such formulations-areusually sufii ciently cohesive as not to require the assistance. of; the present invention. Advantageously, the sensitizer will be a liquid explosive sensitizer, preferably nitroglycerine.

The tacky liquid usediin accordance-the present invention is itself a fuel. Consequently,

it an explosive of proper 1 oxygembalance-isrtocbe prepared, thefuelcharacteristics-of the tacky liq uid should .beconsidered and normally the tacky liquid will; replace part of the a fuel whichrwould'.

otherwise be: present. The oxygen. value :ofrrthe polybutene products used'aherein' will; be about 4.

While the liquid :polybutenezproduct described herein may beused, as stated, to impart cohesiveness to any dynamite lackingin suchpropertyor the desired degreethereof, it isparticularly, an.- plicable. for use inhigh and-low. density ammonia. and. straight dynamites, .particulary dynamites.

where .the explosive 1 sensitizer is. between about. F 233% andabout 20%,, usually between about 5%..

and 15%. For use in small diameters, withdirect.

initiation by a cap, at least about 5% of the explosive sensitizer is generally used, whereas in large diameter cored explosives, as little-as about 2.3%

. ofthmsensitizer may be employed. In the=am-;

moniaidynamites, the-granular ammonium me trateis usually present between about 3% :and about andthe-liquid explosive sensitizer will.

generally be employed in an amount within: the

gredients such'as solid fuels andan oxidizing salt,-

for example sodium nitrate. These. materials. are usually present in such proportions-that the 0x51.- genbalance of the powder, exclusive ofnwrapper, lies between about d-% and +10%. In straight dynamites, the COIIZDUSlItIGIlTTWlH comprise generallya liquid explosive sensitizer, such as is.used in ammonia dynamite, an oxidizing saltother than ammonium nitrate, such as sodium'nitr'ate, solid fuels, and the like. While in a straight dynamite, the sensitizer, for example nitroglycerine, may vary between about 5%. and about 60%; the invention as stated is especially applicable for use indynamite containing not more than about 20% The oxygen balance of the powder, exclusive'of the wrapper, WilliIlSllEHybe between about 35% and-about +10%, generally between. about -'4% and about +10%. Usually the solid iuel' willlbe: present in an amount between. aboutt 3% and about 29% and, as stated, bothtypesaofexplosives. will generally contain an antacid "such as calcium" carbonate in asmall'amount. and either. way, if. desired, contain a gelatinizingegent suchas trocotton in small-amounts. Other: ingredients. cutomarily emplyoyed in suchproducts may :be present, and" in any particular. dynamite product; the proportions of the ingredients employed will provide an explosive of the desired properties.

In preparing the dynamite of the present invention, the tacky liquid isflmixed witnthe: other ingredients in any suitable manner and it is desirable to distribute the liquid throughout the other ingredients.

The invention will be further described by the following; specific .examples Erample 1 A dynamite .was prepared in the usual manner to the following formula Per cent Nitroglycerine 6 Coarse ammonium nitrate 80.4 Sodium nitrate 5 Wood" pulp j 2 .0- F'ineapricot pit pulp L41 Yellow corn flour 2.0"

Chalk" 025 This dynamite packed 143.3 1%" x 8" cartridges per 50 pound case. It was a moist moderately cohesive powder. When the cartridges were cut, however, the powder tended to run out, and this not containing any of the solutions and in which the yellow corn flour was correspondingly increased, which was only slightly moist, barely cohesive, flowed readily when the cartridge was powder caused considerable difficulty by sifting cut, and sifted'through the crimps when handled. out of its shells during transit.

Exam le 4 Example 1-A p A dynamite was made up as in Example 1, ex- Ammonia dyn it s w r pr par d in the cept that .5% of Solution C was substituted for 10 usual manner to the fOll Wln formulael .5% of yellow corn flour. The resulting dynamite packed 146.8 1%," x 8" cartridges per 50 pound b d case. It was cohesive and moist and it held its a c shape when cartridges containing it were unrolled- It packed easily, and there was no Sign e i iiiifiintsiiimisjfii.ififf: 19 8332 8313 83:2 of sifting Sodium Nitrate do 4.3 4.4 4.4 4.4 ll f 'ii rs'i 2'2 5'2 3'2 3'2 ine r10 1 l1 O.. Example 1 B Yellow Co n Flourp 2.0 Another dynamite was made up as in Example E?f&156iiiiffi'fi; s ,glg 13 1 except that 1% of Solution C was substituted for yellow corn flour. This dynamite packed 1 v t f b tl55SSU 210F.. 144.2 1%" x 8" cartridges per 50 pound e a d 2 viifi iii f bg t 220 ssU E210 F3. was more cohesive than the dynamite of Exam- Vlswslty SSU (210 ple The dynamite of Example 4 (a), which con- Eacample 1-0 tained no polybutene product, was slightly moist A fourth dynamite was made as in Examnle 1, and fairly free-running, whereas the explosives except that in this case 2% of Solution C was z 4 3 g t used, replacing all of the corn flour. This dyna were no p 8 exp oslve 0 mite packed 1423 x cartridges per 59 pie 4 (b) was fairly cohesive, whereas the explopound case. It was fully as cohesive as an crdislves of Examples 4 (c) i 4 (d) We}? Shghmy nary Semi ge1atin dynamite and exhibited the tacky and. were characterized by cohesiveness. crawly characteristic of semi-gelatin dynamite.

- Example 5 Example 2 Straight dynamites were prepared in the usual h l n i g gi igii m t e usua ma n91 manner to the following formulae:

Per cent Nitroglycerine 6 40 a b c d Ammonium nitrate 86.50 Ground walnut shells 435 N tr I Per cgn Per cgn Per cgn Per cento r e starch Gzaar s e gl fi li m Nitrate 62.0 62.0 62.0 03.0 Chalk goarse iulphutri niihlfl- 1 .0 This powder was only very slightly moist and Gzgffgd s i if ust f- 3.0 3.0 flowed readily when the cartridge was cut and Chalk i8 sifted through the crimps when handled.

A series of explosives were made up using 0.75% of each of Solutions A, B, C, D, E, F, and G The dynamites Examples 5 (a) and 5 (c) in place of the corresponding amount of starch. which contained no polybutene products, were In all cases, the powder was moist, cohesive, moist, somewhat cohesive but did not extrude crawly, held its shape when the wrapper was rereadily under pressure, whereas the dynamites moved, and did not flow when the cartridge was of Examples 5 (b) and 5 (d) were moist, cohesive, cut. Rough handling of cartridges having parfairly readily extrudable under pressure, and tially open crimps produced no sifting. packed and loaded much better than the explosive of Examples 5 (a) and 5 (c) Example .3 Ammonia dynamites were prepared in the Ewamp'le 6' usual manner to the following formulae:

Ammonia dynamites were prepared in the a b c d e usual manner to the following formulae:

Nitroglycerine Per Oent 6.0 6.0 6.0 6.0 6.0 b d Coarse Ammonium Nitrate 82.0 83.0 82.0 82.0 82.0 a c 2.9 i N p g g-g g-g g-g g-g me pnco I N'trogl e 'ne ce t 8.80 8.80 8.80 8.80 Egg"; 2 8 o iarse ll r nonium Nitrate per D 81.20 81.20 81.20 81.20 6 fi Fine Ammonium Nitrate 2. 50 2.50 2.50 2. 50 solutionl Yellow 0on1 Flour 4.75 4.25 4.00 3.75 ri 3% as 323 as sausa e: do 0:50 0:75 1:00

Character (1) 2 (a) (4) All of the above dynamites were moist, cohesive, crawly, and showed no tendency to sift through hg ggg g y ggggg a partially open crimp. These properties are to i Cohesive, slightly crawly. be contrasted to the same explosive compositions 76 heme, crawly, excellent charmer- Example 7 c b c d Nitroglycerine per cent 10.0 10.0 10. 10.0 Nittocotton o 0. l 0.1 0.1 Fine Ammonium Nitr do 77. 4 77. 4 77.4 77.5 Fine Sodium Nitrate do 4.1 4. 4 5.0 5.0 Bagasse 2. 4 2. 6 3. 0 3.0 Fine Apricot Pit Pulp 0.8 Yellow Corn Flour 3. 7 3.0 1. 1. 5 Sul h 0. 5 0. 5 0. 5 0. 5 1. 0 1. 0 1. 0 1. 0 1.0 1.5 1.5

Character 1 Moist, moderately cohesive.

I Moist, cohesive, barely erawly.,

3 Moist, more cohesive than (b). Slightly crawly. Good body. 4 Much like (0) but slightly. less crawly.

Considerable modification is possible in the composition of the viscous, tacky liquid employed in the explosive composition as well as in the other ingredients of the composition without departing from the essential features of the invention.

I claim:

1. A dynamite comprising an oxidizing salt in granular form, an explosive sensitizer and a solid fuel, and having mixed therewith a voscous liquid product selected from the group consisting of a liquid viscous polybutene and a liquid viscous solution of a solid rubbery polymer dissolved in a liquid polybutene.

2. The dynamite of claim 1 wherein the viscous liquid product is a liquid viscous polybutene.

3. The dynamite of claim 1 wherein the viscous liquid product is a solution of a solid rubbery polybutene dissolved in a liquid polybutene.

4. The dynamite of claim '1 wherein the viscous liquid product is a solution of natural rubber in a liquid polybutene.

5. A dynamite comprising an oxidizing salt in granular form, a liquid explosive sensitizer, a solid fuel, and a viscous liquid polybutene having a viscosity from about 180 SSU (100 F.) to about 2700 SSU (210 F.) in an'amount between about 0.2% and about 5.0% based on the weight of the dynamite composition.

6. The dynamite of claim 5 wherein the viscosity of the viscous liquid polybutene is between about 135 SSU (210 F.) and about 620 SSU (210 F.) and wherein the liquid explosive sensitizer comprises nitroglycerine and is present in an amount less than about 20%.

'7. The dynamite of claim 5 wherein the oxidizing salt comprises ammonium nitrate and wherein the liquid explosive sensitizer comprises nitroglycerine.

8. The dynamite of claim 5 whereinthe oxidizing salt comprises ammonium nitrate, wherein the liquid explosive sensitizer comprises nitroglycerine and is present in an amount less than about 20% and wherein the viscosity of the viscous liquid polybutene is between about 135 $3111 (210 F.) and about 620 SSU (210 F).

9. A dynamite comprising an oxidizing salt in granular form, a .liquid explosive sensitizer, a solid fuel and a tacky liquid comprising a solid rubbery polymer dissolved in liquid polybutene, the tacky liquid product being present in an amount from about 0.2% to about 5.0% based on the weight of the dynamite composition.

10. The dynamite of claim 9 wherein the tacky liquid comprising a solid rubbery polymer dissolved in liquid polybutene contains from about 1 to about 10% of the solid rubber polymer and wherein the solid rubbery polymer is dissolved in a liquid polybutene having a viscosity between about 50 SSU F.) and about 620 SSU (210 F.).

11. The dynamite of claim 9 wherein the tacky liquid comprising a solid rubbery polymer dissolved in liquid polybutene contains from about 1% to about 10% of the. solid rubbery polymer and wherein the solid rubbery polymer is dissolved in a liquid polybutene having a viscosity between about 100 SSU (100 F.) and about 300 SSU (210 F.) and wherein the liquid explosive sensitizer comprises nitroglycerine present in an amount less than about/20%.

12. The dynamite of claim 9 wherein the oxidizing salt comprises ammonium nitrate; wherein the liquid explosive sensitizer comprises nitroglycerine and is present in an amount less than about 20%; and wherein the tacky liquid comprising a solid rubbery polymer dissolved in liquid polybutene contains from about 1% to about 10% of the solid rubbery polymer and wherein the solid rubbery polymer is dissolved in a liquid polybutene having a viscosity between ab)out 50 SSU (100 F.) and about 620 SSU (210 F.

13. The dynamite of claim 12 wherein the solid rubbery polymer is a solid rubbery polybutene.

14. The dynamite of claim 12 wherein the solid rubbery polymer is natural rubber.

WILLIAM J. TAYLOR.

N 0 references cited. 

1. A DYNAMITE COMPRISING AN OXIDIZING SALT IN GRANULAR FORM, AN EXPLOSIVE SENSITIZER AND A SOLID FUEL, AND HAVING MIXED THEREWITH A VOSCOUS LIQUID PRODUCT SELECTED FROM THE GROUP CONSISTING OF A LIQUID VISCOUS POLYBUTENE AND A LIQUID VISCOUS SOLUTION OF A SOLID RUBBERY POLYMER DISSOLVED IN A LIQUID POLYBUTENE. 